1. Field of the Invention
The present invention relates to a vibration motor and a mobile communication apparatus.
2. Description of the Related Art
In recent years, vibration motors that cause a vibrating portion to vibrate in a vertical direction through interaction between a coil and a magnet arranged in a radial direction have often been used as silent notification devices in mobile communication apparatuses or the like or for other purposes. In a vibration motor disclosed in US 2012/0169149, a damper 124 is arranged on an upper surface of a weight 122 arranged opposite to an elastic member 125. The damper 124 prevents the weight 122 from making direct contact with the elastic member 125. A reduction in noise caused by a direct contact between the weight 122 and the elastic member 125 is thus achieved.
The vibration motor disclosed in US 2012/0169149 includes the damper 124 as an additional component. Accordingly, the number of components of the vibration motor and the number of steps for assembling the vibration motor increase, and this may result in an increased production cost of the vibration motor. In a common vibration motor, the vibration frequency of a weight is set close to the natural vibration frequency of an elastic member to increase the amount of vibration of the vibration motor. The addition of the damper 124 as mentioned above may cause the vibration frequency of the elastic member 125 to deviate from the natural vibration frequency thereof due to a contact between the elastic member 125 and the damper 124, which may result in a reduction in the amount of vibration. In other words, the contact of the elastic member 125 with the damper 124 may increase unwanted frequency components other than the natural vibration frequency in the vibration of the elastic member 125, which may result in a reduction in the amount of vibration.